Apparatus and system for precision dispensing of fluids and method of operating the same

Abstract

A fluid dispenser wherein a fixed threaded shaft carries a moveable microprocessor-controlled electric drive motor integrally provided with a shaft extension carrying a plunger for directly contacting and compressing fluid in a syringe barrel to dispense the fluid in accordance with programmed shot volume increments (as small as 0.001 cc, for example) set in the microprocessor, and provided further with provision for the automatic refilling of the syringe barrel upon completion of the fluid dispensing by the plunger

What is claimed is: 
     
       1. A fluid-dispensing system having, in combination, a fixed longitudinal screw shaft carrying in threaded engagement therewith, an electric motor assembly rotatably longitudinally incrementally movable therealong, the motor assembly integrally carrying a depending longitudinal tubular extension terminally provided with a plunger dimensioned to enter and slide within a fluid-containing syringe barrel into direct contact with the fluid therein as the motor assembly is moved along the fixed screw shaft; and a microprocessor for programming the motor energization movement rate, time intervals of movement, fluid volume increments to be dispensed and other parameters, for correspondingly controlling the fluid dispensed from the syringe barrel. 
     
     
       2. The dispensing system of claim 1 wherein a sensor monitors the completion of the dispensing by the plunger and so signals the microprocessor for reversely energizing the motor to withdraw the plunger to the top of the syringe barrel. 
     
     
       3. The dispensing system of claim 2 wherein, upon said completion of the dispensing, the microprocessor automatically, in response to the signal from said sensor, actuates a fluid-filling valve at the bottom of the syringe barrel to enable refilling the syringe barrel. 
     
     
       4. The fluid-dispensing system as claimed in claim 1 wherein the plunger is tapered. 
     
     
       5. The fluid-dispensing system as claimed in claim 4 wherein the bottom of the syringe barrel from which the fluid is dispensed is provided with conically tapered walls similar to the plunger taper. 
     
     
       6. The fluid-dispensing system as claimed in claim 1 wherein the motor is mounted with an encoder for providing pulses to the microprocessor as the motor turns, the number of pulses being a measure of the distance traveled by the motor along the screw thread and thus also of the distance traveled by the plunger within the syringe barrel and the resulting volume of fluid dispensed from the syringe barrel. 
     
     
       7. The fluid-dispensing system as claimed in claim 6 wherein a display is provided for enabling comparison of the programmed fluid volume to-be-dispensed with the actual fluid volume dispensed from the syringe barrel. 
     
     
       8. A method of fluid dispensing under the control of a longitudinal screw shaft carrying an electric motor integrally provided with a depending longitudinal extension terminating in a plunger, the method comprising, fixing the screw shaft against movement; energizing the motor under programmed microprocessor control to cause the motor rotatingly to move longitudinally along the screw shaft in programmed increments; positioning a longitudinal fluid-filled syringe barrel below the plunger to receive the same within the barrel for directly compressing the fluid to dispense the same from the syringe barrel in accordance with said programmed increments to dispense corresponding programmed fluid volumes from the syringe barrel. 
     
     
       9. The method claimed in claim 8 wherein the reaching of completion of the fluid dispensing by the plunger is sensed and signaled to the microprocessor for reversely energizing the motor to cause the plunger to be withdrawn to the top of the syringe barrel. 
     
     
       10. The method claimed in claim 9 wherein the microprocessor, in response to the sensing of the completion of fluid dispensing by the plunger, automatically energizes the opening of a fluid-filling valve for re-filling the syringe barrel. 
     
     
       11. The method claimed in claim 10 wherein the dispensing is controlled in one or more of manual and automatic modes. 
     
     
       12. The method claimed in claim 11 wherein the dispensing is selectively controlled for repetitively dispensing the same volume shots and series of shots of varying volumes. 
     
     
       13. The method claimed in claim 8 wherein the direct contacting of the fluid by the plunger causes substantially instantaneous dispensing upon plunger compression, and the pulling back of the fluid upon plunger retraction. 
     
     
       14. The method claimed in claim 13 wherein upon ending the compressing of the fluid by the plunger, the plunger is slightly retracted to relieve pressure and eliminate fluid dripping form the syringe barrel.